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Acta Cryst. (2009). E65, o25    [ doi:10.1107/S1600536808040397 ]

N-(Diphenylvinylidene)-2,6-diisopropylaniline

W. Imhof

Abstract top

The title compound, C26H27N, was prepared by the elimination of water from N-(2,6-diisopropylphenyl)-2,2-diphenylacetamide. The angle at the central C atom of the cumulene measures 172.5 (4)°. Molecules are connected into infinite chains by intermolecular C-H...N interactions.

Comment top

In the course of a study on the organometallic and catalytic chemistry of aromatic imines (Imhof, 1997a,b) we became interested in the reactivity of the vinylogous keteneimines. The latter are prepared by the elimination of water from the corresponding acetamides by P2O5 in anhydrous pyridine (Stevens & Singhal, 1964).

As expected the molecular structure of the title compound shows an almost linear cumulene system with an angle of 172.5 (4)° at the central C atom. The bonds C1—C2 and C2—N1 show bond lengths of 1.332 (5) and 1.213 (4) Å, respectively. The dihedral angle between the C1—C8—C14 plane and the aromatic substituent at the imine N atom measures to 52.4 (7)° which means that the substituents at the cumulene system do not show the expected orthogonal arrangement. This is most probably caused by the high steric requirements of the two isopropyl groups in ortho-position. A comparison with related aromatic diphenylvinylidene amines from the literature shows that the corresponding dihedral angle is close to 90° if there is no or just one ortho-substituent present in the aromatic group at nitrogen (p-Br-C6H4: 85.6°, Naqvi & Wheatley, 1970; o-Me-C6H4: 88.1°, Jochims et al., 1984; p-(N═C═CPh2)-C6H4: 88.4°, Kuipers et al., 1989; p-Me-C6H4: 83.9°, Naqvi & Wheatley, 1970). If both ortho-positions are substituted the conformation is no longer orthogonal (o-Me2-C6H3: 51.7°, Jochims et al., 1984) as it is also observed for the title compound. The lone pair at nitrogen is involved in a weak intramolecular hydrogen bond (Desiraju & Steiner, 1999) interaction towards H5 leading to the formation of infinite chains.

Related literature top

For the synthetic procedure, see: Stevens & Singhal (1964). For related structures, see: Naqvi & Wheatley (1970); Jochims et al. (1984); Kuipers et al. (1989). For general background, see: Imhof (1997a,b). For properties of weak hydrogen bonds, see: Desiraju & Steiner (1999).

Experimental top

The title compound was prepared following a literature method (Stevens & Singhal, 1964). A sample of 2 g (5.4 mmol) N-(2,6-Diisopropyl-phenyl)-2,2-diphenyl-acetamide was dissolved in 50 ml of anhydrous pyridine. To this solution 5 g P2O5 were added and the mixture was refluxed for 7 h. After cooling the solution was filtered and pyridine was evaporated resulting in a red oily residue. The oil was transferred to a short chromatography column and light petroleum (b.p. 40–60°C) was used to elute a yellow solution of the title compound. Concentration of the solution and cooling to 4°C led to the formation of crystalline material from which the crystal for the structure analysis described herein was collected (yield: 1.56 g, 82%). MS (EI) [m/z, %]: 353 (M+, 80), 338 (C25H24N+, 22), 186 (C13H16N+, 100), 165 (C13H9+, 50), 115 (C9H7+, 19), 91 (C7H7+, 37), 77 (C6H5+, 17), 55 (C4H7+, 11), 41 (C3H5+, 35). 1H NMR (CDCl3, 298 K) [p.p.m.]: 1.11 (12 H, d, 3JHH = 6.8 Hz, CH3), 3.24 (2 H, h, 3JHH = 6.8 Hz, CH), 7.05–7.34 (15 H, m, CHar). 13C NMR (CDCl3, 298 K) [p.p.m.]: 22.4 (CH3), 28.5 (CH), 72.0 (═C), 123.4 (CarH), 125.9 (CarH), 126.3 (CarH), 127.8 (CarH), 128.7 (CarH), 134.8 (Car), 136.2 (Car), 140.8 (Car), 183.4 (═C═).

Refinement top

H atoms were positioned with idealized geometry at distances of 0.95 Å for aromatic C—H functions, 1.00 Å for aliphatic C—H bonds and 0.98 Å for methyl groups and were refined riding on their parent atoms with isotropic thermal parameters of 1.2 times the corresponding values of their parent atoms. In the absence of significant anomalous dispersion effects, Friedel pairs were averaged.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: SET4 (Boer et al., 1984); data reduction: MolEN (Enraf–Nonius, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Siemens, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, presenting the labelling scheme and 40% probability displacement ellipsoids for non-H atoms.
[Figure 2] Fig. 2. Infinite chains of the title compound realized by C—H···O hydrogen bonds.
N-(Diphenylvinylidene)-2,6-diisopropylaniline top
Crystal data top
C26H27NF(000) = 760
Mr = 353.49Dx = 1.141 Mg m−3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 25 reflections
a = 8.082 (4) Åθ = 20.9–35.5°
b = 14.308 (4) ŵ = 0.07 mm−1
c = 17.790 (2) ÅT = 173 K
V = 2057 (1) Å3Cube, pale yellow
Z = 40.3 × 0.2 × 0.2 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer		Rint = 0.065
Radiation source: fine-focus sealed tubeθmax = 24.0°, θmin = 1.8°
graphiteh = −9→0
ω/2θ scansk = −16→16
3554 measured reflectionsl = 0→20
1853 independent reflections3 standard reflections every 120 min
1531 reflections with I > 2σ(I) intensity decay: <0.1%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.103H-atom parameters constrained
S = 0.82 w = 1/[σ2(Fo2) + (0.1319P)2 + 0.5946P]
where P = (Fo2 + 2Fc2)/3
1853 reflections(Δ/σ)max < 0.001
248 parametersΔρmax = 0.15 e Å−3
0 restraintsΔρmin = −0.17 e Å−3
Crystal data top
C26H27NV = 2057 (1) Å3
Mr = 353.49Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 8.082 (4) ŵ = 0.07 mm−1
b = 14.308 (4) ÅT = 173 K
c = 17.790 (2) Å0.3 × 0.2 × 0.2 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer		Rint = 0.065
3554 measured reflectionsθmax = 24.0°
1853 independent reflections3 standard reflections every 120 min
1531 reflections with I > 2σ(I) intensity decay: <0.1%
Refinement top
R[F2 > 2σ(F2)] = 0.040H-atom parameters constrained
wR(F2) = 0.103Δρmax = 0.15 e Å−3
S = 0.82Δρmin = −0.17 e Å−3
1853 reflectionsAbsolute structure: ?
248 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement on F2 for ALL reflections except for 9 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.1809 (3)0.90928 (16)0.93459 (13)0.0304 (6)
C10.2195 (4)1.06100 (19)1.00668 (17)0.0303 (7)
C20.1892 (4)0.98254 (19)0.96930 (15)0.0306 (7)
C30.1148 (4)0.9958 (2)1.12860 (17)0.0363 (7)
H30.06260.94701.10120.044*
C40.1008 (4)0.9981 (2)1.20605 (18)0.0421 (8)
H40.04010.95081.23140.051*
C50.1749 (4)1.0691 (2)1.24668 (18)0.0414 (8)
H50.16361.07171.29980.050*
C60.2652 (4)1.1358 (2)1.20919 (18)0.0408 (8)
H60.31781.18411.23700.049*
C70.2810 (4)1.1341 (2)1.13188 (16)0.0339 (7)
H70.34441.18071.10710.041*
C80.2041 (4)1.06391 (18)1.09007 (17)0.0289 (6)
C90.1828 (5)1.2310 (2)0.97473 (17)0.0404 (8)
H90.10501.23701.01440.049*
C100.2210 (5)1.3071 (2)0.9299 (2)0.0494 (9)
H100.16951.36560.93950.059*
C110.3325 (6)1.2993 (3)0.87148 (19)0.0569 (11)
H110.35771.35210.84110.068*
C120.4071 (5)1.2144 (3)0.85749 (19)0.0544 (10)
H120.48301.20850.81700.065*
C130.3720 (4)1.1378 (2)0.90200 (17)0.0408 (8)
H130.42481.07970.89230.049*
C140.2595 (4)1.1454 (2)0.96113 (15)0.0314 (6)
C150.0304 (4)0.7690 (2)0.90761 (15)0.0300 (7)
C16−0.1020 (4)0.7236 (2)0.87388 (17)0.0374 (7)
H16−0.11410.65800.87960.045*
C17−0.2159 (4)0.7728 (2)0.83219 (19)0.0432 (8)
H17−0.30710.74090.81030.052*
C18−0.1993 (4)0.8682 (2)0.82167 (17)0.0406 (7)
H18−0.27810.90070.79180.049*
C19−0.0683 (4)0.9176 (2)0.85429 (16)0.0335 (7)
C200.0419 (4)0.8665 (2)0.89897 (14)0.0282 (6)
C210.1642 (4)0.7162 (2)0.95050 (17)0.0364 (7)
H210.19170.75400.99610.044*
C220.3218 (5)0.7091 (2)0.9033 (2)0.0461 (8)
H22A0.35540.77160.88690.055*
H22B0.30080.66980.85920.055*
H22C0.41030.68120.93360.055*
C230.1115 (6)0.6197 (2)0.9776 (2)0.0545 (10)
H23A0.19970.59261.00850.065*
H23B0.09060.57930.93420.065*
H23C0.01030.62521.00760.065*
C24−0.0519 (4)1.0221 (2)0.84131 (18)0.0396 (8)
H240.06581.03920.85210.048*
C25−0.1593 (5)1.0765 (2)0.8963 (3)0.0586 (10)
H25A−0.13151.05810.94780.070*
H25B−0.27611.06280.88650.070*
H25C−0.13941.14360.88990.070*
C26−0.0872 (5)1.0502 (3)0.7602 (2)0.0623 (11)
H26A−0.20431.03920.74880.075*
H26B−0.01831.01290.72620.075*
H26C−0.06181.11670.75340.075*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0354 (14)0.0255 (12)0.0303 (12)0.0015 (11)−0.0040 (11)−0.0019 (10)
C10.0340 (16)0.0248 (14)0.0322 (14)−0.0013 (14)−0.0016 (13)−0.0040 (12)
C20.0334 (15)0.0293 (15)0.0291 (13)0.0027 (13)−0.0018 (13)0.0026 (13)
C30.0431 (17)0.0271 (13)0.0387 (15)−0.0057 (15)−0.0027 (15)−0.0019 (13)
C40.0489 (18)0.0383 (16)0.0391 (16)−0.0007 (17)0.0021 (16)0.0087 (14)
C50.0473 (19)0.0491 (18)0.0279 (14)0.0042 (17)−0.0023 (15)0.0052 (14)
C60.0512 (18)0.0367 (16)0.0347 (15)−0.0019 (17)−0.0147 (15)−0.0037 (13)
C70.0391 (16)0.0298 (14)0.0329 (15)−0.0042 (15)−0.0033 (13)0.0013 (12)
C80.0297 (14)0.0254 (13)0.0315 (14)0.0021 (13)−0.0019 (13)−0.0005 (11)
C90.0502 (19)0.0352 (16)0.0358 (16)−0.0024 (16)−0.0036 (16)0.0020 (13)
C100.065 (2)0.0340 (16)0.0491 (19)−0.0055 (18)−0.0197 (19)0.0057 (15)
C110.079 (3)0.059 (2)0.0328 (17)−0.040 (2)−0.0121 (19)0.0129 (17)
C120.067 (2)0.063 (2)0.0333 (17)−0.031 (2)−0.0003 (18)−0.0005 (16)
C130.0444 (18)0.0420 (16)0.0360 (15)−0.0120 (16)0.0041 (14)−0.0062 (15)
C140.0365 (15)0.0316 (14)0.0260 (13)−0.0075 (15)−0.0038 (12)−0.0018 (12)
C150.0369 (16)0.0290 (14)0.0242 (13)0.0021 (13)−0.0013 (14)−0.0039 (12)
C160.0438 (18)0.0333 (15)0.0351 (15)−0.0013 (15)−0.0010 (15)−0.0049 (14)
C170.0385 (18)0.0483 (18)0.0427 (17)−0.0083 (16)−0.0062 (16)−0.0083 (16)
C180.0399 (17)0.0486 (18)0.0334 (15)0.0025 (17)−0.0105 (14)−0.0015 (14)
C190.0338 (16)0.0365 (16)0.0303 (14)0.0024 (14)0.0029 (13)−0.0040 (13)
C200.0319 (14)0.0284 (13)0.0242 (13)0.0035 (13)0.0007 (12)−0.0048 (11)
C210.0454 (18)0.0283 (14)0.0354 (15)0.0048 (14)−0.0075 (15)−0.0029 (13)
C220.0431 (18)0.0409 (17)0.054 (2)0.0099 (16)−0.0056 (17)−0.0066 (16)
C230.065 (2)0.0357 (17)0.063 (2)0.0021 (19)−0.015 (2)0.0084 (17)
C240.0386 (17)0.0363 (16)0.0438 (17)0.0075 (15)−0.0028 (15)0.0061 (14)
C250.055 (2)0.0350 (17)0.086 (3)0.0103 (18)0.011 (2)−0.0023 (19)
C260.060 (2)0.064 (2)0.064 (2)0.000 (2)−0.010 (2)0.030 (2)
Geometric parameters (Å, °) top
N1—C21.218 (4)C15—C201.406 (4)
N1—C201.428 (4)C15—C211.523 (4)
C1—C21.328 (4)C16—C171.376 (5)
C1—C141.490 (4)C16—H160.9500
C1—C81.489 (4)C17—C181.385 (5)
C3—C81.393 (4)C17—H170.9500
C3—C41.383 (4)C18—C191.399 (5)
C3—H30.9500C18—H180.9500
C4—C51.384 (5)C19—C201.400 (4)
C4—H40.9500C19—C241.519 (4)
C5—C61.374 (5)C21—C231.523 (5)
C5—H50.9500C21—C221.529 (5)
C6—C71.381 (4)C21—H211.0000
C6—H60.9500C22—H22A0.9800
C7—C81.395 (4)C22—H22B0.9800
C7—H70.9500C22—H22C0.9800
C9—C101.385 (5)C23—H23A0.9800
C9—C141.393 (5)C23—H23B0.9800
C9—H90.9500C23—H23C0.9800
C10—C111.380 (6)C24—C261.525 (5)
C10—H100.9500C24—C251.521 (5)
C11—C121.379 (6)C24—H241.0000
C11—H110.9500C25—H25A0.9800
C12—C131.381 (5)C25—H25B0.9800
C12—H120.9500C25—H25C0.9800
C13—C141.395 (4)C26—H26A0.9800
C13—H130.9500C26—H26B0.9800
C15—C161.388 (5)C26—H26C0.9800
C2—N1—C20129.6 (3)C16—C17—H17119.6
C2—C1—C14116.9 (3)C18—C17—H17119.6
C2—C1—C8120.5 (3)C17—C18—C19121.0 (3)
C14—C1—C8122.5 (2)C17—C18—H18119.5
N1—C2—C1172.5 (3)C19—C18—H18119.5
C8—C3—C4121.1 (3)C18—C19—C20117.0 (3)
C8—C3—H3119.5C18—C19—C24120.0 (3)
C4—C3—H3119.5C20—C19—C24123.0 (3)
C5—C4—C3120.2 (3)C15—C20—C19122.6 (3)
C5—C4—H4119.9C15—C20—N1115.4 (2)
C3—C4—H4119.9C19—C20—N1121.9 (3)
C6—C5—C4119.1 (3)C23—C21—C15114.2 (3)
C6—C5—H5120.4C23—C21—C22110.3 (3)
C4—C5—H5120.4C15—C21—C22110.4 (3)
C5—C6—C7121.3 (3)C23—C21—H21107.2
C5—C6—H6119.4C15—C21—H21107.2
C7—C6—H6119.4C22—C21—H21107.2
C6—C7—C8120.2 (3)C21—C22—H22A109.5
C6—C7—H7119.9C21—C22—H22B109.5
C8—C7—H7119.9H22A—C22—H22B109.5
C3—C8—C7118.1 (3)C21—C22—H22C109.5
C3—C8—C1120.9 (3)H22A—C22—H22C109.5
C7—C8—C1120.9 (3)H22B—C22—H22C109.5
C10—C9—C14119.5 (3)C21—C23—H23A109.5
C10—C9—H9120.3C21—C23—H23B109.5
C14—C9—H9120.3H23A—C23—H23B109.5
C11—C10—C9121.0 (3)C21—C23—H23C109.5
C11—C10—H10119.5H23A—C23—H23C109.5
C9—C10—H10119.5H23B—C23—H23C109.5
C12—C11—C10119.5 (3)C19—C24—C26112.8 (3)
C12—C11—H11120.2C19—C24—C25110.8 (3)
C10—C11—H11120.2C26—C24—C25111.5 (3)
C13—C12—C11120.4 (3)C19—C24—H24107.1
C13—C12—H12119.8C26—C24—H24107.1
C11—C12—H12119.8C25—C24—H24107.1
C12—C13—C14120.3 (3)C24—C25—H25A109.5
C12—C13—H13119.9C24—C25—H25B109.5
C14—C13—H13119.9H25A—C25—H25B109.5
C9—C14—C13119.3 (3)C24—C25—H25C109.5
C9—C14—C1121.4 (3)H25A—C25—H25C109.5
C13—C14—C1119.2 (3)H25B—C25—H25C109.5
C16—C15—C20117.8 (3)C24—C26—H26A109.5
C16—C15—C21122.1 (3)C24—C26—H26B109.5
C20—C15—C21120.0 (3)H26A—C26—H26B109.5
C17—C16—C15120.7 (3)C24—C26—H26C109.5
C17—C16—H16119.7H26A—C26—H26C109.5
C15—C16—H16119.7H26B—C26—H26C109.5
C16—C17—C18120.8 (3)
C20—N1—C2—C1−169 (2)C8—C1—C14—C13137.9 (3)
C14—C1—C2—N182 (2)C20—C15—C16—C171.3 (4)
C8—C1—C2—N1−101 (2)C21—C15—C16—C17−176.5 (3)
C8—C3—C4—C50.5 (5)C15—C16—C17—C181.3 (5)
C3—C4—C5—C6−1.4 (5)C16—C17—C18—C19−1.3 (5)
C4—C5—C6—C71.0 (5)C17—C18—C19—C20−1.3 (5)
C5—C6—C7—C80.3 (5)C17—C18—C19—C24179.4 (3)
C4—C3—C8—C70.8 (5)C16—C15—C20—C19−4.1 (4)
C4—C3—C8—C1179.7 (3)C21—C15—C20—C19173.8 (3)
C6—C7—C8—C3−1.2 (4)C16—C15—C20—N1−179.8 (2)
C6—C7—C8—C1179.9 (3)C21—C15—C20—N1−1.9 (4)
C2—C1—C8—C3−18.4 (5)C18—C19—C20—C154.0 (4)
C14—C1—C8—C3158.0 (3)C24—C19—C20—C15−176.7 (3)
C2—C1—C8—C7160.5 (3)C18—C19—C20—N1179.5 (3)
C14—C1—C8—C7−23.1 (4)C24—C19—C20—N1−1.3 (4)
C14—C9—C10—C110.7 (5)C2—N1—C20—C15−139.4 (3)
C9—C10—C11—C120.1 (5)C2—N1—C20—C1944.9 (4)
C10—C11—C12—C13−0.7 (6)C16—C15—C21—C23−21.2 (4)
C11—C12—C13—C140.6 (5)C20—C15—C21—C23161.0 (3)
C10—C9—C14—C13−0.7 (5)C16—C15—C21—C22103.7 (3)
C10—C9—C14—C1−178.5 (3)C20—C15—C21—C22−74.0 (3)
C12—C13—C14—C90.1 (5)C18—C19—C24—C26−41.8 (4)
C12—C13—C14—C1178.0 (3)C20—C19—C24—C26139.0 (3)
C2—C1—C14—C9132.2 (3)C18—C19—C24—C2584.0 (4)
C8—C1—C14—C9−44.3 (4)C20—C19—C24—C25−95.2 (4)
C2—C1—C14—C13−45.6 (4)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···N1i0.952.723.554 (4)146
Symmetry codes: (i) −x+1/2, −y+2, z+1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···N1i0.952.723.554 (4)146
Symmetry codes: (i) −x+1/2, −y+2, z+1/2.
references
References top

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